Apparatus for the control of highway crossing signals



April 16,1940. P. H. CRAGO 2,197,425

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed July 22,1958 3 Flag/22012 .C'omaczfr INVENTOR Patented Apr. 16, 1940 PATENTOFFICE 3 APPARATUS FOR THE CONTROL OFI-IIGH- WAY CROSSING SIGNALS PaulH. Crago, Wilkinsburg, Pa., assignor to The Union Switch & SignalCompany, Swissvale, Pa., a corporation of Pennsylvania Application July22, 1938, Serial No. 220,693

16 Claims.

My invention relates to apparatus for the control of highway crossingsignals, and particularly to apparatus for controlling a highwaycrossing signal located at the intersection of a highway and a railwaytrack over which trains move in both directions.

An object of my invention is the provision, in apparatus of thecharacter described, of novel and improved means for operating thehighway crossing signaluntil trains completely clear the intersection.Other objects and advantages, of my invention will appear as thespecification progresses.

The apparatus for the control of highway crossing signals set forth inthe present application is somewhat similar to that disclosed in acopending application Serial No. 240,521 filed on November 15, 1938, byHenry S. Young for Apparatus for the control of highway crossingsignals,

and certain features set forth in the present application are broadlycovered in the said copending application.

I shall describe two forms of apparatus each embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawing; Fig. 1 is a diagrammatic View showing oneform of apparatus embodying my invention. Fig. 2 is a diagrammatic viewshowing a modified form of the'apparatus of Fig. 1 and also embodying myinvention.

Referring to Fig. 1, the reference characters I and I a designate thetrack rails of a stretch of railway over which traffic moves in bothdirections. Rails I and, I a, are divided by means of the usualinsulated track joints 2 into relatively long operating sections D-E andF-G which are separated from each other by a relatively short positiveoperating section E-F. Section E F is intersected by a highway H; andlocated adjacent the intersection is a highway crossing signal S, whichmay be any one of the well-known forms, but which, as shown here, is anaudible signal in the form of an electric bell. Sections D-E and FGusually will be of such length that an adequate warning period forhighway users of the approach of the train to thehighway is provided.Section E-F usually will be of such length that the section completelyincludes the highway intersection.

Sections DE and E-G are each provided with a track circuit comprising atrack battery 3 connected across the track rails at one end of eachsection and a track relay, designated by the reference characters TRIand 'I'R3, respectively, connected across the track rails at the otherend.

Section E--F is also provided with a trackcircuit which may be tracedfrom one terminal of battery 3 of section E-F through rail .I, wire athen through four branch paths to wire 9; a first path of whichcomprises front fiagman contacts 4 and 5 of an interlocking relay IR, tobe referred to later; a second path of which comprises front contacts Iand 6 of relays TRB and TRI, respectively; a third path of whichcomprises front fiagman contactt of relay IR and front contact 6 ofrelay TRI; and a fourth path of which comprises front contact I of relayTR3 and front fiagman contact 5 of relay IR; wire 9, the winding ofrelay TRZ, wire- I0, and rail Ia to the other terminal of battery S ofsection E-'F.

The interlocking relay IR, referred to previously, may be of anysuitable type, such as, for example, the relay covered by United StatesLetters Patent No. 1,799,629, granted to W. K. Lockhart and T. J. OMearaon April '7, 1931. This type of relay is well known and is characterizedby the fact that when the left-hand winding WI is deenergized, thedownward movement of the armature associated therewith operates amechanical lockingdevice which keeps the arma ture associated with theright-hand winding W2 locked up in approximately its mid position, sothat a subsequent deenergization of winding W2 while winding WI is stilldeenergized cannot'close back contacts-4a, I2 and I3 Similarly, if theright-hand winding W2 is first to become deenergized, then back contacts5a, l4 and I5 are prevented from closing when the left-hand wind- 'ingWI becomes deenergized during the interval that winding W2 is stilldeenergized. Relay IR is also provided with front contacts 5 and 4asso-v ciated with windings WIand. W2, respectively, which have what Ishall term fiagman adjustment. That is to say, these contacts remainclosed when the associated armature isin its locked up position.WindingWI of relayIR is energized over a circuit passing from oneterminal B of a suitable source of current, such as a battery not shown,through front contact I6 of relay 'I'R2, front contact ll of relay TRI,and Winding WI of interlocking relay IR to the other terminal C of thesource of current. Winding W2 is energized over a circuit passing fromterminal B through front contact I8 of relay TR? and the winding W2 ofinterlocking relay IR, to terminal C. As willbe explained hereinafter,the interlocking relay IR functions as directional means for preventingthe operation of the crossing signal by relay TRI .or TR3 when sectionD-E, or

FG becomes occupied by trains receding from the intersection.

Signal S is energized over a circuit passing from terminal B throughthree branch paths to the operating element of signal S and to terminalC, a first path including back contact I5 of winding WI of relay IR; asecond path includingback contact I3 of winding W2 of relay'IR'; and athird path including back contact I9 of relay TRZ.

A shunt path, controlled jointly by track relay TRZ and winding W2 ofrelay IR, is provided around the operating winding of relay TRI and maybe traced from the left-hand terminal of relay 'I'RI through wire 20,back contact I2 of winding W2 of relay IR, wire 2|, back contact 22 ofrelay TR2, and wire 23 to the right-hand terminal of relay TRI.Similarly, a shunt path, controlled jointly by track relay TR2 and,winding WI of relay IR, is provided. around the winding of relay 'IR3and may be traced from the righthand terminal of relay TR3 throughwire'24, back contact 25 of relay TR2, back contact I4 of winding WI ofrelay IR, and wire 2'? to the lefthand terminal of relay TR3.

The apparatus is in its normal condition, as shownin Fig. 1, whensections D-E, EF and F--G are unoccupied. In this condition of theapparatus, the track relays TRI, TR2 and TR3 are energized, windings WIand W2 of relay IR are likewise energized, and signal S is deenergized.I shall now assume that an eastbound train, that is, a train moving fromleft to right in Fig. l, enters section D-E and thereby shunts relay TRIso that relay TRI releases. The release of relay TRI opens front contactI1 and thereby opens the circuit for winding WI so that winding WIreleases to establish the energizing circuit for signal S at backcontact I5. Signal S now becomes energized and exhibits its warning tohighway users of the approach of the train.

It is to be noted'that when relay TRI releases, front contact 6 of relayTRI opens to open the previously mentioned second and thirdbranch pathsprovided in the track circuit for section E-F; and that when winding WIreleases, front contact 5 of winding WI opens to open the first andfourth branch paths provided in the track circuit for section E-F, sothat relay TR2 releases. It should further be noted that back contact I4also closes when winding WI releases so that when back contact 25 ofrelay TRZ closes,

the shunt path around the winding of relay .TR3 is completed,whereupon'relay TR3 releases to open front contact I8 so that winding W2of relay IR isdeenergized and releases. It should further benotedthatback contact. I9 of relay TR2 closes tov complete the third branch pathin the circuit for signal S. It follows that when an eastbound trainenters section 13-351, relay TRI isshunted and releases. The release ofrelay TRI opens the circuit, for winding WI ,whereby winding WI releasesto its full released DQSitiOn and initiates theoperationof signal S. Therelease of relay TRI and winding WI opens the track circuit for section.E-.F so that relay TR2 releases to establish the shunt path around thewinding of relay TBS in the track circuit for section FG so that relayTR3 releases. The release of relay TR3 opens the circuit for winding W2sothat the armature associated with thatjwinding is released and isengaged by the locking feature of relay IR.

When thetrain enters track section E-F, the wheels and axles of thetrain shunt the track rails, but this action serves no useful purpose atthis time, since track relay TR2 is released.

When the train vacates section D-E, relay TRI picks up since its shuntpath around its operating winding is open at back contact I2 of windingW2 of relay IR, to close front contacts 6 and ,I'I.. Front contact I'Inow prepares the circuit for winding WI, but winding WI is retainedreleased since its energizing circuit is open at front contact I6 ofrelay TRZ. Front contact 6 of relay TRI completes the third branch pathprovided in the track circuit for section E-F, but relay TRZ is retainedreleased by the shunt provided across rails I and I a of section E--F bythe wheels and axles of the train. The reason for open-circuiting thetrack circuit for section E-F will now become apparent, since thisopen-circuiting efiects the release of relay TR2 prior to the trainentering section E-F. It follows that since relay TR2 is released priorto the entrance of the train on section E-F', the train need not createthe low resistance shunt to the rails of section E-F necessary to effectthe release of track relay TRL2, but need create only sufiicientshunting to prevent the pick-up of relay TR2.

When the train enters track section FG the Wheels and axles of the trainshunt the rails I and Ia of section F-G, but at this time no usefulpurpose is served, the relay TR3 having been released in response to therelease of relay TR2 and Winding WI.

When thetrain vacates track section EF and completely clears highway H,relay TR2 picks up over its energizing circuit including the previouslymentioned third branch path to closefront contact I6 and to open backcontacts I9, 22 and 25. The opening of back contact IQ of relay TRZopens the third branch path in the energizing circuit for signal S; andthe closing of front contact I6 completes the circuit for winding WI sothat winding WI becomes energized. Front contact 5 of winding WI nowcloses and back contacts I4 and I5 open. The opening of back contact I5of relay WI opens the first branch path in the circuit for signal S withthe result that signal S ceases to exhibit its warning. It should benoted that back contact 25 of relay TR2 and backcontact I4 of windingWI, which are interposed in the shunt path around the winding of relayTR3, are now open, but relay TR3 is retained deenergized by virtue ofthe train shunt in section F--G. The reason for providing the shunt patharound the winding of relay T123 will nowbecome apparent, since therelease of relay TR3, resulting from the releasing of relay TRI andwinding WI when the train enters section D'E, efiects the release ofwinding W2 and consequent locking up of the armature of winding W2'toestablish directional control of signal S prior to the train shuntingthe track relay TR3 by entering section F-G. It follows that loss ofdirectional control is avoided in the event a train such as alightengine passes rapidly from section E--F to section F-G, since winding WIcannot become reenergized prior to winding W2 becoming deenergized. Itcan be seen that the directional control for the signal, whereby relayTR3 is prevented from operating the signal when the train occupiessection FG in receding from the intersection, is established when thetrain first enters the operating section DE in approaching theintersection, and false operation of the signal due to loss ofdirectional control is prevented;

When the'train vacates section F-G, relay M ergizing circuit for windingW2.

TR3 becomes energized to close front contacts I and I3, winding W2picking up over front contact I8. The apparatus is now restored to itsnormal condition. a

The operation of the apparatus of Fig. 1 for a westbound train issimilar to that just-described for an eastbound train. That is to say,the entrance of a westbound train upon section F-G shunts relay TR3 sothat relay TR3 releases to open front contact I and thereby open thesecond and fourth branch paths provided in the track circuit for sectionand to open front contact l8, thereby opening the circuit for winding W2of relay IR. Winding W2 now releases to establish the energizing circuitfor signalS at back contact I3, and signal S becomes energized todisplay its warning to highway users. The release of winding W2 alsocloses back contact I2, thereby preparing the shunt path around thewinding of relay TRI, and opens front flagman contact l to open thefirst and third branch paths provided in the track circuit for sectionE-F. The track circuit for section E--F now being open-circuited, relayTR2 releases, thereby opening front contact it to open the circuit forwinding WI whereby winding WI releases its armature to its locked upposition. The release of relay TR2 also closes back contacts I9, 22 and25. The closing of back contact I9 completes the third branch path inthe circuit for signal S, and the closing of back contact 22 completesthe short circuit path around the winding of relay 'IRI whereby relayTRI releases. It follows that when a westbound train enters section F-G,relay TR3 and winding W2 are released, thereby initiating the operationof signal S, and relay TRZ is released to insure that signal S willoperate until the train vacates section E-F and clears the highway.Also, relay TRI and winding WI are released so that the armature ofwinding WI is engaged by the interlocking feature of relay TR; thusavoiding possible loss of the directional control for signal S.

When the train enters section E'-F and estab lishes the train shuntacross the rails of section EF', no useful purpose is served by thistrain shunt at this time since relay TR2 is released when the trainenters section F--G.

Ordinarily, the head end of the train enters section DE to shunt relayTRI prior to the rear of the train vacating section F-G. Under thisordinary condition, the entrance of the train on section DE establishesthe train shunt in section DE. The train shunt in section DE, however,serves no useful purpose at this time since relay TRI is released whenthe train enters section F G'. Hence, under the ordinary conditions,when the train vacates section FG, relay TR3 picks up to close frontcontacts I and I8. The closing of front contact I completes the fourthbranch path provided inthe track circuit for section E-F, but relay TR2is now held deenergized by the train shunt in section EF. The closing offront contact I8 completes the en- Winding W2 now picks up to open backcontact I3 and thereby opens the second branch path in the circuit forsignal S, but signal S is retained energized over its branch circuitincluding back contact I9 of relay TRZ. Back contact I2 also opens whenwinding W2 picks up, thereby opening the shunt, path around the windingof relay TRI, but relay TB! is now held released by the train shunt insection DE. When the train vacates section E-Fand clears theintersection, relay 'I'RZ picks up to open back contact I9, therebyterminating the operation of signal S, and to close front contact I6 toprepare the circuit for winding WI. When the train vacates section DE,relay TRI picks up to close front contact I'I, thereby completing thecircuit for winding WI so that winding WI picks up.

In the event that the train is short, so that the rear of the trainvacates section F-G prior to the head end entering section D.E, afurther function arises for open-circuiting the track circuit forsection E- F whereby relay TR2 releases. When a train is short enough tobe entirely within section E-F so that it vacates section F-G and thuspermits relay TR3 and winding is not yet shunted by the train. Thepicking up of relay TRI, however, does not complete the energizingcircuit for winding WI since that circuit is open at front contact I6 ofrelay. TR2, so that winding WI remains released and maintains thedirectional control for signal S. When the short train enters sectionDE, relay TRI is shunted and releases to open the circuit for winding WIat front contact I I., When the train vacates section E-F, relay TR2picks up, opening back contact I9 and thereby opening the circuit forsignal S to terminate the operation of signal S, and closing frontcontact I6 to prepare the circuit for winding WI. When this short trainvacates section DE, relayTRI picks up to close front contact H tocomplete the circuit for winding WI so that winding WI picks up.

It follows that for a westbound train, the

open-circuiting of the track circuit for section EF results in providingthe condition thata low resistancetrain shunt is not required to rejlease relay TRZ, the same as for an eastbound train, and relay TRZreleased provides the function of retaining the-established directionalcontrol for a train short enough to be entirely within section E.--F.Furthermore, when a westbound train-passes rapidly from section FG tosections E-Fand DE, loss of directional control is avoided since windingWI is deenergizecl and released while the train is approaching theintersection in section F-G.

It is to be understood that while I have shown (in Fig. l) relay TR2 asbeing controlled by relay TRI or, TR3 open-circuiting the track circuitfor section EF, relay TR2 may be controlled by any'other suitable means,such as by providing a .short circuit path around the winding of relayTRZ, this short circuit path being controlled by relay TRI or TR3. N

It should be noted thatrelay IR is provided with contacts 5a and 4aassociated with windings WI and W2, respectively, and suitablyinterconnected so that in the event relays TRI and TR3 mightaccidentally be released at the same instant, thereby permitting bothwindings WI and W2 of relay IR to assume their full releasedpositions,.relay TR2 is not open-circuited and does not release tocomplete the shunt paths around relays 'I'RI and TR3. It follows thatwhen the conditions causing the simultaneous release of relays TRIand'TR3 are removed, relays TRI and TR3 will again become reenergized.

Referring now to Fig. 2, the track circuit for section DE may now betraced from one terminal of battery 3 of section DE through rail I, wire28, the winding of relay "IRI, wire 29,

- through rail I, wire 33, winding of relay TR3,

wire 34, then two branch paths to wire 35; one path comprising wire 34a,front contact 36 of relay 'I'R2 and wire 35a; the other path comprisingwire 34b, front "flagman contact 31 of winding WI of relay IR and wire35b; wire 35 and rail Ia to the other terminal of battery 3; The trackcircuit for section E-F may be traced from one terminal of battery 3 ofsection EF, through wire 38, rail I, the winding of relay TR2, rail Ia,wire 39, then two branch paths to wire 40; one branch pathcomprisingwire 4|, front contact 6 of relay TRI, and wire 43; the otherbranch path comprising wire 44, front fiagman contact 5 of winding WI ofrelay IR, and wire 46; wire 40, then two branch paths to wire 41; onepath comprising wire 48, front contact I of relay TR3, and wire 50; theother path comprising wire 5|, front ffiagman contact 4 of winding W2 ofrelayIR, and wire 53; wire 41 and .regulating resistance R to the otherterminal of battery 3.

Winding WI of relay IR is provided with a pick-up circuit passing fromterminal B through front contact II; of relay TR2, front contact I! ofrelay TRI, and the winding WI of relay IR to terminal C. Winding W2 issimilarly provided with a pick-up circuit passing from terminal Bthrough front contact I6of relay TR2, front contact I8 of relay TR3 andthe'winding W2 of relay IR to terminal C. -"Windi'ngs WI and W2 are eachprovided with stick circuits; a

stick circuit for winding WI passing from terminal B through frontflagmanf contact 51 of winding WI, front flagman contact 58 of windingW2, front contactllcf relay 'I'RI and wind ing WI to terminal'C; and astick circuit for winding W2 passing from terminal B through frontflagman contact 51 of winding WI, front fflagmanf contact 560i windingW2, front contact I8 of relay 'I'R3, and winding W2 to terminal C.

The operating circuit for signal S is the same as traced for Fig. 1,except that front flagman contact 51 of winding WI is interposed in thebranch circuit governed by back contact I3 of winding W2. r I

In the normal condition of the apparatus, that is, when sections D-E,E.F and FG are unoccupied, the apparatus is in the condition shown inFig. 2. In this normal condition, relays TRI, TR2 and TR3 are energized;the pick-up and stick circuits for windings WI and W2 of relay IR arecompleted so that both windings of relay IR are energized; and. signal Sis deenergized.

I shall now assume that an. eastbound train enters section D--E of Fig.2 so that relay TRI is shunted and releases to open front contact II.

This opens both the pick-up and stick circuits for winding, WI of relayIR, and winding WI releases to'complete the circuitfor signal 8' overback contact I5. Signal S is now energized, and displays its warning totrafic operating on the highway H. Front contact 6 also'opens when relay'I'RI releases, and front contact 5 likewise opens when winding WIreleases. The opening of these contacts, which areinterposed in thetrack circuit 'for section E-F between wires 39 a'nd40, opens thattrack-circuit so that relay TR2 also releases. The release of relay TR2opens front contacts 3|, 36 and I6, and closes backcontact I9, thelatter of which completes its branch path for signal S. v

The openingof front contact 36 of relay TRZ (front contact 31 of windingWI being opened when winding WI releases) opens the track circuit forsection F-G so that relay TRS releases to open front contacts 7 and I 8,the opening of. the latter contact opening both the pick-up and stickcircuits for winding W2 so that winding W2 also releases. It followsthat when an eastbound train enters section D-E, relay TRI and windingWI release, thereby initiating the operation of signal S, andestablishing directional control thereof. The release of relay TRI andwinding WI also opens the track circuits for sections EF and F-G so thatrelays TR2 and TR3 release. The release of relay TR2 opens the circuitfor winding W2 so that the armature associated with winding W2 isreleased and engaged by the locking feature of relay IR.

When the train enters track section EF, the wheels and axles of thetrain shunt the track rails, but this action serves no useful purpose atthis time.

, When the train vacates section DE, relay TRI becomes energized and.closes front contacts 6 and II, the closing of front contact 6completing the circuit for relay TR2 across wires 39 and 40, but relayTR2 is retained deenergized by the train shunt in section EF. As wasexplained hereinbefore, since the release of relay TR2 is effected bythe train entering section D-E, the train need not create the lowresistance shunt to the track rails of section EF necessary to releaserelay TRZ, but need only provide sufiicient shunting to prevent thepick-up of relay 'I'R2. It should be noted that since battery 3 ofsection E-F is disconnected from the track rails of section EF when thetrain occupies section DE, a saving in battery current is effected.

When the train enters track section FG, the wheels and axles of thetrain shunt the track rails, but no useful function is served at thistime by this action. When the train vacates section EF, and completelyvclears highway H, relay TRZ becomes reenergized to close front contacts3|, 36 and I6 and to open back contact I9, the latter contact openingthe third branch path in the circuit for signal S. The closing of frontcontact I6 of relay TR2 completes the pick-up circuit for winding WI sothat winding WI becomes reenergized to open back contact I5 and therebyopen the circuit for signal S, and to close front contacts 5, 31 and 51,the last contact completing the stick circuit for winding WI. Signal Snow becomes deenergized and no longer displays its warning exhibit tohighway traflic. Relay TR3 is now held deenergized by virtue of thetrain shunt in section F-G, since front contact 36 of relay TR2 andfront contact 31 of winding WI are now closed so that each now completesthe track circuit for the section FG across wires 34 and 35. As waspointed out previously in connection with Fig. l, the release of relayTR3 is effected by the release of relay TRI and winding WI to insurethat when a light engine passes rapidly from section EF to section F--G, winding W2 is deenergized and engaged by the interlocking feature ofrelay IR prior to winding WI becoming energized, thereby avoidingpossible loss of directional control of signal S.

When the train vacates section FG, relay TR3 becomes reenergized toclose front contacts I and I8, the closing of front contact I8completing the pick-up and stick circuits for winding W2 so that windingW2 becomes reenergized. The apparatus is now in its normal condition.

The operation of the apparatus-of Fig. 2 for a westbound train issimilar to that just described for an eastbound train. That is to say; awestbound train entering section F-G initiates the operation of signal Sand establishes directional control by releasing relay T33 and windingW2 of relay IR. Also, thetrack circuits for sections DE and E-F areopened so that relays TR2 I and TRI release; and the circuit for windingWI is opened whereby winding WI releases to its locked position. Whenthe train vacates section F-G, relay TR3 becomes reenergized, but signalS is retained energized by virtue of its circuit controlled by backcontact l3 of winding W2 of relay IR. since winding W2 is controlled byrelay TR2. When the train completely passes highway H and vacatessection EF, relay TRZ and winding W2 of relay IR. pick up to stop theoperation of signal S. Then, when the train vacates section DE, relayTRI, and winding WI of relay IR become reenergized, and the apparatus isre-' stored to its normal condition.

It is to benoted that windings WI and W2 are each provided with a stickcircuit so that an accidental shunting of track relay TR2, andconsequent opening of the pick-up circuits for windings WI and W2, doesnot deenergize windings WI and W2. Thus, it can be seen that a windingof relay IR can only become released when the track relay associatedwith that winding is ,released to interrupt both the pick-up and stickcircuits for that winding. It should further be noted that relay IR isprovided with back contacts d and 4a, associated with windings WI andW2, respectively, which are suitably. connected so that an accidentalshunting at the same instant of both track relays 'I'RI and TR3,resulting in the simultaneous release of both windings WI and W2 totheir full released position, does not open-cricuit relay TR2 with theresult that re-, lay TR2 does not release. Since relay TRZ does notrelease, relays TRI and T123 are not open-. circuited at front contacts3| and 36, respectively, of relay TR2, so that when the shunt is removedfrom the windings of relays TRI and TR3, they will again becomereenergized.

One advantage of apparatus embodying my invention is the provision ofnovel and improved.

means effective to operate a highway crossing signal protecting theintersection of a highway and a railway track over which traflic movesin both directions until trains completely clear the intersection.

Although I have herein shown and described only two forms of apparatusembodying, my invention, it is understood that various. changes andmodifications may be made therein within 65 the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track; divided into a firstsection and a third section a third't-rack relay associatedwith' saidthirdsec tion, directional means controlled by said first and thirdtrack relays for causing said signal to operate whenever a train isapproaching the in- V tersection, circuit means governed by said firstclears the intersection.

2. In combination, a-stretch of railway track divided into a firstsection and a third section separated from each other by a secondsection intersected by a highway, a highway crossing signal located atsuch intersection, a track circuit'for said first section including afirst track relay, a track circuit for said second section including asecond track relay, a track circuit for said third section including athird track relay, operating means governed by said first relay or saidthird relay and operative according as said first section or said thirdsection is first entered by a train approaching the highway foroperating said signal, circuit means governed by said first relay orsaid third relay and operative according as said first section or saidthird section is first'entered by a train approaching the highway foropen-circuiting said second track circuit, and other operating meansgoverned by said second relay for operating said signal.

3. In combination, a stretch of railway track divided into a firstsection and a third section separated from each "other by a secondsection intersected by a highway, a highway crossing signal located atsuch intersection, a first track' a third track relay associated withsaid third section, means controlled bysaid first track relay andeffective when said first track section is entered by a trainapproaching the highway for initiating the operation of said signal andfor releasing said second track relay and said third track relay, meanscontrolled by said second track relay to operate said signal, and meanscontrolled by said third track relay and efiective when said thirdsection is entered by a train approaching the highway for initiating theoperation of the signal and for releasing said second track relay andsaid first track relay.

4. In combination, a stretch of railway track divided into a firstoperating section anda second operating section separated by a positiveoperating section, said positive operating section intersected by ahighway, a signal for controlling trafiic on. said highway at suchintersection, a first track relay associatedwith said first operatingsection, a second track relay associated with said second. operatingsection, a third track relay means controlled by the track relayassociated" with said one of said operating-sections for releasing thetrack relay associated with the-other of said operating sections andsaid third track relay, meanscontrolled by said third track relay forgoverning said operating means to operate said signal until the trainclears the highway, and directional means controlled by the trackrelaysassociated with said operating sections for preventing the trainfrom operating said signal 5. In combination, a stretch of railway trackdivided into a first section and a third section separated from eachother by a second section intersected by a highway, a highway crossingsignallocated at such intersection, an interlocking relay having a firstwinding and a second winding, a first circuit for said signal governedby a back contact of said first winding, a second circuit for saidsignal governed by a back contact of said second Winding, a first trackrelay associated withsaid first track section for controlling said firstwinding of thejinterlocking relay, a second track relay associated withsaid second track section, a third track relay associated with saidthird track section for. controlling said second winding of theinterlocking relay, a third circuit for said signal governed byabackcontact of said second track relay,'.means governed jointly by saidfirst track relay and said first winding of the interlocking relayoperative to release said second track relay; and said third trackrelay, and means governed jointly by said third track relay and saidsecond winding of the interlocking relay operative to release saidsecond track relay and said first track relay.

6. In combination, a stretch of railway track divided into a firstsection and a third section separated from each other by a secondsection intersected by a highway, a highway crossing signal located atthe intersection, an interlocking relay having a first winding and asecond winding, a first energizing circuit 'for said signal controlledby back contact of each winding of the inter,- locking relay, a firsttrack relay associated with said first track section, an energizingcircuit for said first winding of the interlocking relay including afront contact of said first relay, a third track relay associated withsaid third track circuit, an energizing circuit for said second windingof the interlocking relay including a front contact of said third relay,a second track relay associated with said second track section, a secondenergizing circuit for said signal including a back contact of saidsecond track relay, means controlled jointly by said first track relayand said first winding of the interlocking relay operative to releasesaid second track relay and said third track relaywhenever a train firstenters said first section in approaching the intersection,

ing relay having a first winding and a second winding, a first circuitfor said signal governed by a back contact of said first winding or ofsaid second winding of the interlocking relay, a first track relayassociated with said first section for governing said first Winding ofthe interlocking relay, a second track relay associated with said secondsection, a third track relay associated with said third section forgoverning said second winding of the interlocking relay, means includinga front contact of said first relay and a front contact of said firstwinding of the interlocking relay for controlling said second relay,

other means including a front contact ;of said third relay and a frontcontact of said second winding of the interlocking relay for controllingsaid second relay, a second circuit for said signal including a backcontact of said second relay, and meansincluding back contactsof saidsecond relay for controlling said first and said third relays.

8. In combination, a stretch of railway track divided into a firstsection and a third section separated ,from each other by a secondsection intersected by a highway, a'highway crossing signal located atsuch intersection, a track circuit for said first section including thewindingof a first track relay, a track circuit for saidsecond sectionincluding the winding of a second track relay, a track circuit for saidthird section including thewinding of a third track relay, operatingmeans governed by said first relay or said third relay and effectiveaccording as said first section or said third section is first enteredby a train approaching the intersectionfor operating said signal, otheroperating means governed by said second track relay for operating saidsignal, circuit means governed by said first trackrelay or said thirdtrack relay andeiiective according as said first section or said thirdsection is first entered by the train approaching the intersec-v tion toopen-circuit said second track circuit, other circuit means governed bythe one of said first and said third track relays associated with thetrack section entered by the train in appreaching the intersection forproviding a short circuit path around the winding of the other one ofsaid first and said third track relays, and directional means governedby said first and said third track relays. V

9. In combinations, stretch of railway track divided into a'firstsection and a third section separated from each other by'a'secondsection intersected by a highway, at highway crossing signal located atsuch intersection, a track circuit for saidfirst section including afirst track relay, 9; track circuit for said second section including asecond track relay, a track circuit for said third section including athird track relay, operating means governed by said'first track relay orsaid third track relay and effective according as said first section orsaid third section is first entered bya' train approaching the"intersection for operating said signal, other operating means governedby said second track relay for operating said signal, circuit meansgoverned by said first track relay or'said third track relay andeiiective according as said first/section or said third section is first'entered'by the train approaching the intersection for open-circuitingsaid second track circuit, directional means governed by said firsttrack relay and said third track relay, and other circuit means governedby said first track relay or said third track relay and effectiveaccording as said first section or said third section is first enteredby the'train approaching the intersection for open-circuiting saidthirdtrack cirfirst section, including the winding of a first track 76:;

relay, said first relay governing said first winding of the interlockingrelay, a track circuit for said third section including the winding ofa'third track relay, said third track relay governing said secondwinding of the interlocking relay, a track circuit for said secondsection including the winding of a second track relay, a secondenergizing circuit for said signal including a back contact of saidsecond relay, means governed jointly by said first relay and said firstwinding of the interlocking'relay and effective whenever a train firstenters said first section in approaching the intersection foropen-circuiting said second track circuit, other circuit means governedjointly by said third track relay and said second winding of theinterlocking relay and efiective whenever a train first enters saidthird section in approaching the intersection for open-circuiting saidsecond track circuit, a short circuit path around the winding of saidfirst relay serially including a back contact of said second relay and aback contact of said second winding of the interlocking relay, and ashort circuit path around the winding of said third relay seriallyincluding a back contact of said second relay and a back contact of saidfirst winding of the interlocking relay.

11. In combination, a stretch of railway track divided into a firstsection and a third section separated from each other by a secondsection intersected by a highway, a highway crossing signal located atsuch intersection, an interlocking relay having a first winding and asecond winding, a first energizing circuit for said signal including aback contact of each winding of the interlocking relay, a track circuitfor said first section including a first track relay, said first relaygoverning said first winding of the interlocking relay, a track circuitfor said third section including a third track relay, said third relaygoverning said second winding of the interlocking relay, a track circuitfor said second section including a second track relay, a secondenergizing circuit for said signal including a back contact of saidsecond relay, circuit means governed jointly by said first relay andsaid first winding of the interlocking relay efiective whenever a trainfirst enters said first section in approaching said intersection foro-pen-circuiting said second track circuit, other circuit means governedjointly by said third relay and said second winding of the interlockingrelay effective whenever a train first enters said third section inapproaching said intersection for opencircuiting said second trackcircuit, means governed jointly by said second track relay and saidsecond winding of the interlocking relay for open-circuiting said firsttrack circuit, and means governed jointly by said second track relay andsaid first Winding of the interlocking relay for open-circuiting said.third track circuit.

12. In combination, a stretch of railway track divided into a firstsection and a third section separated from each other by a secondsection intersected by a highway, a highway crossing signal located atsuch intersection, a first track relay associated with said firstsection, a second track relay associated with said second section, athird track relay associated with said third section, an interlockingrelay having a first windingv and an operating circuit for said signalgoverned byv aback contact of each winding of the interlocking relay.

13. In combination, a stretch of railway track divided into a firstsection and a third section separated from each other by a secondsection intersected by a highway, a highway crossing signal located atsuch intersection, a first track relay associated with said firstsection, a second track relay associated with; said second section, athird track relay associated with said third section, an interlockingrelay having a first winding and a second winding-said first and secondwindings each having a pick-up circuit and a stick circuit, said firstrelay governing both said pick-up and stick circuits of said firstwinding, said third relay governing both said pick-up and said stickcircuits of said second winding, said second relay governing saidpick-up circuit of said first winding and said pick-up circuit of saidsecond winding, and an operating circuit for said signal governed bysaid first winding and by said second Winding.

14. In combination, a stretch of railway track divided into a firstsection and a third section separated from each other by a secondsection intersected by a highway, a highway crossing signal located atsuch intersection, a first track relay for said first section, a secondtrack relay for said second section, a third track relay for said-thirdsection, an interlocking relay having two windings, operating circuitmeans controlled by each of said two windings for operating said signal,control circuit means for a first of said two windings controlledjointly by said first track relay and said second track relay, controlcircuit means for the second of said two windings controlled jointly bysaid third track relay and said second track relay, circuit meanscontrolled jointly by said first track relay and said first winding andeffective whenever a train first enters said first section inapproaching the intersection for causing the release of said secondtrack relay, and other circuit means controlled jointly by said thirdtrack relay and said second winding and effective whenever a train firstenters said third section in approaching the intersection for causingthe release of said second track relay.

15. In combination, a stretch of railway track divided into a firstsection and a third section separated from each other by a secondsection intersected by a highway, a highway crossing signal located atsuch intersection, a first track relay for saidfirst section, a secondtrack relay for said second section, a third track relay for said thirdsection, an interlocking relay having two windings, operating circuitmeans controlled by each of said two windings for operating said signal,control circuit means for a first of said two windings controlledjointly by said first track relay and said secondtrack relay, controlcircuit means for the second of said'two'windings controlled jointly bysaid third track relay and said second track relay, circuit meanscontrolled jointly by said first track relay and said first winding andefiective whenever a train first enters said first section inapproaching the intersection for causing the release of said third trackrelay, and other circuit means controlled jointly by said thirdtrackrelay and said second winding and effective whenever a train firstenters said third section in approaching the intersection for causingthe release of said first track relay.

16. In combination, a stretch of railway track divided "into a firstsection and a third section separated from each other by-a secondsection intersected by a highway, a highway crossing signal located atsuch intersection, a first track relay for said first section, a secondtrack relay for said second section, a third track relay for said thirdsection, aninterlocking relay having two windings, operating circuitmeans controlled by each of said two windings for operating said signal,control circuit means for a first of said two windings controlledjointly by said first track relay and said second track relay, controlcircuit means for the second of said two windings controlled jointly bysaid third track relay and said second track relay, circuit meanscontrolled jointly by said first track relay and said first winding andefiective whenever a train first enters said first section inapproaching the intersection for causing the release of said secondtrack relay and said third track relay, and other circuit meanscontrolled jointly by said third track relay and said second winding andeffective whenever a train first enters said third section inapproachingthe intersection for causing the release of said first trackrelay and said second track relay.

PAUL H. CRAGO.

